This invention relates to the magnetic information card art, and more particularly, to the encoding of such cards, that is, magnetically recording information thereon in binary data form for subsequent readout. Such cards are commonly referred to as mag-stripe cards because the information is normally recorded along one or more data tracks on a stripe of magnetic material running lengthwise of the card. A typical mag-stripe card is disclosed in U.S. Pat. No. 3,946,206 for Magnetic-Type Information Card and Method and Apparatus for Encoding and Reading, issued Mar. 23, 1976 in the name of John C. Darjany.
In the encoding of a card, it is, of course, necessary that the magnetic data be placed on the card in a predetermined desired position which takes into account the design of the readout equipment. In the most usual type of commercial operation, the card is encoded by the card manufacturer to the user's specification, and the manufacturer has sophisticated and highly accurate encoding equipment available to ensure that the magnetic data is properly positioned on the card. One example of encoding equipment which might be employed by a card manufacturer is disclosed in FIG. 13 of the above referred to Darjany U.S. Pat. No. 3,946,206. As there shown, the card is automatically moved past a recording head at a constant speed by a constant speed drive. A photoelectric cell detects exactly when the card is positioned with respect to the recording head at the desired "start recording" point and signals the control circuit to initiate the serial release to the recording head of binary data previously stored in a storage register. A constant frequency generator provides a clock pulse signal which regulates the rate of release of the data according to its fixed frequency. It is evident that with such a system the placement of a given amount of information on the card can be accurately controlled, the constant frequency of the clock circuit and the constant speed of the card drive system determining the spacing of the data bits on the card. For example, exactly 32 bits of data can be accurately positioned on a predetermined one inch length of the magnetic stripe.
A need exists, however, for a simpler encoding system especially adapted for use in the field, i.e. by the ultimate user, who may not have the above described specialized and expensive encoding equipment, or who may not have a need for its degree of accuracy. In particular, a need exists for relatively simple, inexpensive, and compact information card encoding equipment which avoids the need for both the constant frequency clock pulse generator and the constant speed drive of the encoding system of U.S. Pat. No. 3,946,206.